Mixture control device



March 11, 1947.

M. J. KITTLER ETAL MIXTURE CONTROL DEVICE Filed July 19, 1944 MJKillZer lqrl Hillier):

Patented Mar. 11,1947

MIXTURE CONTROL DEVICE Milton J. Kittler and Carl F. Schorn, Detroit, Mich., asslgnors to George M. Holley and Earl Holley Application July 19, 1944, Serial No. 545,668

4 Claims. (Cl. 261-72) of the fuel economizer valve and as background the carburetor itself is shown diagrammatically.

In the diagram, I3 is the air entrance, I4 and I5 are the streamlined throttles which with the nozzle l6 forms a variable venturi. I1 is an opening in the throttle l5, which communicates Venturi suction to the mixture control device through the pipe I.

The air flows to a supercharger I3, and the pressure created in this supercharger is transmitted through pipe l2 to the mixture control device.

The fuel is supplied from the diaphragm fuel chamber l9, and the pressure in this chamber I9 is controlled by the air pressure in the chain? bers 20 and 2|, which are in communication with each other.

re-established in chamber 3|! through a small air passage 38. A bridge element 35 is carried by the two diaphragms 33 and 3|, and, it carries a valve 43 and a spring 54, which pushes the valve 43 up against the valve seat surrounding the opening 42.

In the position shown, the throttles I4 and I5 are almost in the idling position so that the supercharger is creating a pressure very much less than atmospheric. Hence, as the diaphragm 33 is subjected toatmospheric pressure, it pushes the valve 43 to the right so that-the valve 43 keeps the opening 42 in line with the opening in valve 43, and this applies venturi suction from the throat |4--|5, pipe l0, valve H and then through the pipe H to the chamber -2| so as to reduce the fuel flow.

The moment the valve 29 closes, the spring 32 is the only force active, as the pressure on diaphragm 3| equals the pressure on diaphragm 33. Hence, valve 43 moves to the left and closes the opening at 42; hence, the mixture becomes normal. When throttle lever 21 is moved counterclockwise around pivot.53 to open the throttles, the engine increases in speed and with it the supercharger. Then the sub-atmospheric pressure imposed on chamber is transformed and eventually rises so as to equal atmospheric pres- The pressure in these chambers is controlled by the pressure in the air entrance annular chamber 50 through a restriction 40. The mixture control device, the subject of this application, is connected to the chambers 20 and 2| 'through the pipe sure when the spring 32 pushes the valve 43 to the left and again the opening 42 is closed and again the mixture becomes normal. This takes place just before the supercharger generates a pressure equal to atmosphere, because the spring 32- is equivalent to a pressure of 2" of mercury. A stop 55, which limits the travel of the valve 43 and bridge element to the left, has no and I5. The threaded adjustment of a bolt 5| provided on the upper end of lever 28 by engaging with a rod 52 also closes the valve 29 so as to stop the flow of air through a pipe l2, which is connected to the outlet from the supercharger l8, so that the supercharger pressure has no longer any influence on the mixture control device.

Until the valve 29 is closed by the rod 52 and adjustable bolt 5| and by the clockwise rotation of the lever 21 around pivot 53 and lever 28, supercharger pressure exists in the chamber 30. When the valve 29 is closed by rod 52 engaging with adjustable bolt 5|, atmospheric pressure is function except to prevent strain on the diaphragms 3| and 33. It will be noted that the super-atmospheric pressure of the supercharger l8 never has any effect on the movement of the valve 43, because before such a pressure is generated, the valve 43 has moved. Atmospheric pressure acting on diaphragm 33 opens the valve 43. The spring 32closes valve 43.

The valve 4| is a manually operated valve operated by a lever 44, which can be used to disconnect the venturi suction in pipe |ll from the mixture control device.

Operation In the normal operation, the valve 29 is wide open and the diaphragm 3| responds to the supercharger pressure. If the pressure falls below 28" Hg. of mercury, the diaphragm 33, being at 30" Hg. (sea level) drags the valve 43 into line, allowing 2" of mercury for the spring 32 is immediately restored to normal by the action of the supercharger pressure, which pushes the valve 43 to the left. The mixture ratio is restored to normal because the pressure in the chambers 20 and 2| is equal to the pressure in a'pproachesits open position, the higher pressure chamber 50, because suction created in throat.

"- is no longer applied through restrictions 4| and 42 to'cause a flow of air throughrestric tion 40 to lower the pressure in chamber -2|. Whenever the throttle moves to the idle position when the valve 29 cuts off flow through the pipe l2 for the same reason the mixture is reduced to normal as the valve 43 is moved to the left by the spring 32. The small opening 38 admits atmospheric pressure to the chamber 30 so that. 1

any suction in chamber 30 quickly disappears after valve 29 is closed.

It must be understood that super-atmospheric pressure is never responsible for the movement v 'of the valve 43; the supercharger merely-re;-

stores the pressure in the pipe l2 to a pressure equal that in the air entrance (chamber 50) less that equal to spring 32, which is equal to 2" Hg.

When this happens, the throttles l4 and I5 are then moreopen than as shown. The pressure of the atmosphere acting on the left of the diaphragm 33 is substantially equal to that in the chamber 50, which is the pressure in the air entrance. It is this pressure which'opens the valve 43; The spring 32 closes the valve 43. As no provision has been made for altitude, this specific invention'is intended for-low flying aircraft and for marine engines. Y

What we claim is: 1. In an internal combustion engine having carburetor air throttling means for 'said carburetor of the variable venturi type, a fuel supply chamber, a diaphragm on one side of said "chamber, an air chamber on the other side of said diaphragm, a restricted air passage connecting the air chamber with air at the atmospheric pressure of the entering air, a second restricted air passage connecting the air chamber with .the suction created by said engine in the throatpf the variable venturi formed by said throttle, an-automatic valve adapted to open and a moving wall therefor connected to said auto pheric pressure, an unrestricted air passage connecting said second air chamber to the engine,

side of said throttle, spring means for moving said valve so that when the throttle approaches its closed position, the engine suction resulting therefrom moves said moving wall and said automatic valve against the action of said spring to open said second passage and when the throttle resulting therefrom permits said automatic valve to be moved in response to said spring to close said second passage.-

2. A device as set forth in claim 1 in which there is a shut-oil valve in said unrestricted air passage and a restrictedair'passage connecting said second air chamber to the atmosphere and a mechanical connection from the-throttle to said shut-oil valve arranged so as to close said unrestricted air passage and thus permit the atmospheric pressure acting throughsaid restricted opening to pushsaid automatic valve so as to close said second restricted air passage when the throttle is moved to its idle position.

3. A device as set forth in claim 1 in which there is a manually controlled shut-off valve arranged in series with said automatic air valve in said second air passage. A

4. A device as set forth in claim 1 in whic there is a shut-oil valve in said unrestricted air passageand a restricted air passage connecting second air chamber to the atmosphere and a I mechanical connection from the throttleto said matic valve and responsive on one side to atmosshut-ofi valve arranged so as to close saidunrestricted ail passage and thus permit the atmospheric pressure acting through said restricted opening to push said automatic valve'so as to close said second restricted air passage when the r throttle'is moved to its idle position anda second 1 manually controlled shut-off valve arranged ,in

series with said automatic valve in said second dim of this patent:

rmrrEn STATES PATENTS Number Name Date 2,228,000 Chandler Jan. "I, 1941 2,159,173 Mennesson May 23, 1939 2,232,392 Kittler .Feb. 18, 1941 1,979,834 I Jenks Nov. 6, 1934 1,945,189 Goodman Jan. 30,1934

1,948,135 Sands Feb. 20, 

